Day 21 (part1)

1 files changed, 66 insertions, 0 deletions

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+import strutils
+import sequtils
+import tables
+import strformat
+
+type
+  Node = ref object of RootObj
+    left, right: string
+    val: int
+
+  AddNode = ref object of Node
+  SubNode = ref object of Node
+  MulNode = ref object of Node
+  DivNode = ref object of Node
+
+var nodes: Table[string, Node]
+
+method calc(node: Node): int =
+  node.val
+
+method calc(node: AddNode): int = 
+  nodes[node.left].calc() + nodes[node.right].calc()
+
+method calc(node: SubNode): int = 
+  nodes[node.left].calc() - nodes[node.right].calc()
+
+method calc(node: MulNode): int = 
+  nodes[node.left].calc() * nodes[node.right].calc()
+
+method calc(node: DivNode): int = 
+  nodes[node.left].calc() div nodes[node.right].calc()
+
+proc `$`(node: Node): string =
+  fmt"val: {node.val}, left: {node.left}, right: {node.right}"
+
+proc parseLine(line: string): void =
+  let tokens = line.split(": ")
+  let id = tokens[0]
+  let ops = tokens[1].split(" ")
+
+  # if single token -> its a number
+  if ops.len() == 1:
+    nodes[id] = Node(val: ops[0].parseInt())
+  else:
+    let left = ops[0]
+    let right = ops[2]
+    case ops[1]:
+      of "+":
+        nodes[id] = AddNode(left: left, right: right)
+      of "-":
+        nodes[id] = SubNode(left: left, right: right)
+      of "*":
+        nodes[id] = MulNode(left: left, right: right)
+      of "/":
+        nodes[id] = DivNode(left: left, right: right)
+      else:
+        assert(false)
+
+proc parseFile(): void =
+  let lines = readFile("./input.txt").strip().splitLines()
+
+  for line in lines:
+    parseLine(line)
+
+parseFile()
+echo nodes["root"].calc()